Arrangement for positive yarn tension control on double row warp knitting machine

ABSTRACT

THE PRESENT ARRANGEMENT IS PARTICULARLY ADAPTED FOR VARYING THE FEED OF SELECTED SETS OR GROUPS OF WARP YARNS DURING THE KNITTING OF TUBULAR FABRIC ON A DOUBLE ROW WARP KNITTING MACHINE. THE SELECTED VARIATION IN THE FEED RATE OF THE WARP YARNS IS PARTICULARLY ADAPTED FOR KNITTING TUBULAR HOSIERY BLANKS WHEREIN A DIFFERENT STITCH PATTERN IS EMPLOYED IN KNITTING THE REINFORCED AND PLAIN KNIT SECTIONS OF THE HOSIERY BLANK.

March 2, 1971 M. A. PERRIER 3,566,621

ARRANGEMENT FOR POSITIVE YARN TENSION CONTROL ON DOUBLE ROW WARPKNITTING MACHINE 4 Sheets-Sheet 1 Filed July 14. 1969 Inventor MARILJSANTOINE PEREJEE BY flwwfljfizlf, 1%.M9 JM A T702 IVE V5 March 2, 1971 M.A. PERRIER 3,566,621

' ARRANGEMENT FOR POSITIVE YARN TENSION CONTROL ON DOUBLE ROWWARPKNITTING MACHINE Filed July 14, 1969 4 Sheets-Sheet 2 Inventor.- MAramsANTOINE- Peszmea BY ma @JJMJ;W,M#M

A TTOE/VEVS March 2, 1971 M. A. PERRIER ARRANGEMENT FOR POSITIVE YARNTENSION CONTROL ON DOUBLE ROW WARP KNITTING MACHINE 4 Sheets-Sheet 5Filed July 14, 1969 HI] .HIH

V H V H V Fig. 10

a n t/Mm 0E. mz flw a... E M, m VD.% M% /A m MW AJ 5M m 2 A I. M f Y 5March2, 1971 M. A. PERRIER 3,556,621

' ARRANGEMENT FOR POSITIVE YARN TENSION CONTROL ON DOUBLE ROW WARPKNITTING MACHINE Filed July 14, 1969 4 Sheets-Sheet 4 Ljia Iii 1. .413.0

35 103 75 Fig. 71.

Inventor.- Mmams ANTOINE PERRIER BY wzzwwgw wwwm ATTORNEYS United StatesPatent 0 3,566,621 ARRANGEMENT FOR POSITIVE YARN TENSION CONTROL ONDOUBLE ROW WARP KNITTING MACHINE Marius Antoine Perrier, Lyon, France,assignor to Somarco S.A., Fribourg, Switzerland Filed July 14, 1969,Ser. No. 841,192 Claims priority, application Germany, July 13, 1968, P17 60 879.6 Int. Cl. D04b 23/02 US. CI. 6687 5 Claims ABSTRACT OF THEDISCLOSURE The present arrangement is particularly adapted for varyingthe feed of selected sets or groups of warp yarns during the knitting oftubular fabric on a double row warp knitting machine. The selectedvariation in the feed rate of the warp yarns is particularly adapted forknitting tubular hosiery blanks wherein a different stitch pattern isemployed in knitting the reinforced and plain knit sections of thehosiery blank.

This invention relates to an arrangement for the positive continuoustake-off of yarn or thread from multiple warp beams of flat warpknitting machines with two needle rows, particularly Raschel knittingmachines for knitting seamless hosiery blanks in the form of one or moretubular knitted fabrics. Each tube contains continuous repetitions ofthe hosiery lengths and is formed in two circumferential halves whichare knit on different needle rows. The halves are knit along adjacentportions of the two needle rows and the halves are interknitted andjoined together by alternately knitting across and between neighboringneedles of the two needle rows. The thread take-off speed of at leastone warp beam feeding each needle row is variable in two or more stepsto permit the knitting of different stitch patterns of the group of warpyarns. An independent shift gear transmission is provided and the speedsof the warp beams are infinitely readjustable, in accordance with theyarn tension, to compensate for their decreasing diameters.

Contrary to ordinary tubular knitted fabrics, such as for night caps,gas light mantles, or the like, tubular fabrics for ladies hosieryrequire reinforcements for certain sections which later form the toe,the sole, the heel and the welt of the finished stocking, in order toprovide for the special stresses on these parts. One part of thesereinforcements, i.e., those for the toe, the sole,- the heel are onlyneeded on one circumferential half of the hosiery tube whereas the partforming the welt is reinforced on the whole circumference of the hose.

Whereas the above-noted prior types of tubular knitted fabrics have beenexclusively made on circular knitting machines as weft knitted fabrics,it has been recently suggested in French Pat. 1,321,541 that flat warpknitting machines with two needle rows, among which is in particular theRaschel knitting machine, may be used to knit tubular hosiery fabricblanks. In this type of machine, the alternate interlacing of wholegroups of warp yarns on the two needle rows produces the circumferentialhalves of the hose and thereby yields essentially higher manufacturingperformance and reduces the manufacturing cost considerably. By means ofthe integral knitting of two different kinds of stitch patterns with atleast two rows of guide bars on each needle row, run-proof fabric canalso be knit.

To manufacture reinforced hose sections, the type of stitch pattern ischanged either on one or both needle rows. If two or even more sets ofwarp yarns are fed to each needle row, it is sufficient to change thetype of ice stitch pattern being formed of one of such sets of warpyarns. While the main part of the stockings, particularly the leglength, includes a tricot pattern integrally knit with a plain patternto form a double yarn stitch loop tricot fabric, the plain pattern isreplaced in the reinforced sections by an open or closed twill pattern.The thereby increased thread consumption is compensated for by steplesschange of the take-off speed of the respective group of warp yarns bymeans of a special change gearing which is independent of the drives ofall the other warp beams, such as is known from the French Pat. No.1,488,796. Since the reinforcements are needed for the hose toe on theone circumferential half and for the sole and heel on the othercircumferential half while reinforcements are required for theknitted-on welt on the whole hose circumference, at least one warp beamfeeding to each needle row has to be separately driven over anindependent change gearing which allows the take-off speed to be adaptedto the changing type of stitch pattern being knit of the groups of warpyarns being furnished by these warp beams. Further, by means ofwell-known infinitely variable transmissions which are preferablycontrolled by the thread tension (Swiss Pat. No. 414,924), thedifferently decreasing warp beam diameters are compensated for in such away that the thread take-off speed for a certain type of stitch patternis kept constant, independently of the effective warp beam diameter.

Despite the most careful setting of the control devices for suchinfinitely variable transmissions used with two or multi-step changegearings, it is still not possible to obtain sufficiently uniformtension and feed of the yarn in those parts of the hose in which bothcircumferential halves of the tubular knitted fabric have the samestitch pattern. Even slight deviations yield streaks along the junctureconnecting the two circumferential halves, which even visually stays onthe finished hose after it has been finally shaped by steam or otherheat treatment and thus reduces the market value of the hosiery, even ifit does nglt completely ruin it or renders the hosiery unmarketa e.

It is an object of this invention to eliminate such streakingness in thehosiery fabric. To this end, the corresponding independent changegearings of the warp beams corresponding to the two needle rows arepreceded by a common infinitely variable transmission which is dependenton the yarn tension of the corresponding groups of warp yarns of thesebeams. The feeds to the two needle rows and the changes of the shifts ofthe gear transmissions are correspondingly programmed so that thecoordlnation of the two circumferential halves of the tubular knitfabric to the two needle row changes from hose length to hose length.

By changing the coordination of the two hose halves to the two needlerows, the different amounts of thread consumption caused by theunilateral reinforcement feeds on the warp beams engaged in thisprocess, is constantly compensated so that their diameters decrease in asubstantially uniform manner. Under these conditions the infinitelyvaria'ble transmission of such a pair of warp beams maintains an exactconformity of the warp takeoff speed and the same gear ratios of theshift gear transmissions as they have during the knitting of the legportion of the hose.

In the following, the invention is explained in detail by referring tothe drawings, in which- FIG. 1 is a side elevation of a partiallyreinforced ladies stocking in finished form, illustrating its shapeafter boarding;

FIG. 2 is a side elevational view of one side of a tubular knittedhosiery blank, from which the stocking of FIG. 1 is formed;

FIG. 3 is a perspective view of the tubular knitted hosiery blank ofFIG. 2;

FIG. 4 is a somewhat schematic transverse vertical sectional view of aRaschel knitting machine with two needle rows for making tubular knittedhosiery blanks of the type shown in FIGS. 2 and 3;

FIG. 5 is a fragmentary plan view of the needle beds, schematicallyillustrating the longitudinal distribution of the latch needles and holdor blind needles adjacent the end areas of each tubular blank;

FIGS. 6-10 show the point diagram for the laying of the yarns and theformation of the stitch patterns in the different hose sections; and

'FIG. 11 is a somewhat schematic view showing the principal drive andcontrol devices for the positively driving of the warp beams of theRaschel knitting machine.

The ladies stocking, broadly indicated at in FIG. 1, includes areinforced toe 11, sole 12, heel 13 and welt 14 with the reinforcedareas being cross-hatched while the upper part of the foot 15 and theleg length 16 remain unreinforced.

The first step in the formation of such a hose includes knitting ahosiery blank, represented as one continuous tubular knit length A (FIG.2). The upper end of this tubular knit blank is reinforced at a on thetwo circumferential halves v and h and over the same length to form aturned and hem-med welt 17, on the finished hose, while the bottomsection represents different lengths of reinforcements a and 11 on thetwo circumferential halves v and h. The reinforcement a on the backcircumferential half is longer and forms the heel and sole of thefinished hose while the shorter reinforcement a on the frontcircumferential half forms the hose toe after the tubular hosiery blankhas been cut along a curved line 18 (FIG. 2) which is adapted to theshape of the foot and stitched at the same time along the curved edges.A comparison between FIGS. 1 and 2 shows the different lengths offormation of the reinforcements a and u while the upper foot part 15 isunreinforced as desired and the stitches are the same as the stitches ofthe leg length 16.

FIG. 4 shows the general construction of a Raschel knitting machine withtwo needle rows for simultaneously knitting a plurality of such tubularhosiery blanks as side by-side warp knit fabrics. For example, it ispossible to make simultaneously twelve knitted stockings on the samemachine. As is known, the Raschel knitting machine is equipped with tworows of active latch needles Z and Z and a number of blind or holdneedles, reasons explained later on. Latch needle leads 21 and 22 arelocated on each side of grooved needle beds 23 and 24 which are fixed onrespective needle bars 25, 26, carried by levers 27, 28. The levers 27,28 swing around the pivots 29, 30 and are driven by push rods 31, 32 androll guides which are supported on levers 33, 34. Cam discs 37, 38 arefixed on the synchronously driven main shafts 35, 36 of the machine andimpart alternate raising and lowering movements to the needle bars 25,26.

Guide bars I through VIII are supported for lengthwise shifting orshogging movement on spaced supports 39 which are fixed along the lengthof a guide bar swinging shaft 40, only one of such supports 39 beingshown in FIG. 4. The guide bars are provided with yarn guide fingerswhich swing across the needles by means of a lever 41 and a connectorrod 42. A lever 43 is connected to the rod 42 and is provided with aroll guide which rides on a cam disc 44 fixed on the main shaft 35.Swinging movement is thus imparted to the shaft 40 in the properproportion to the upward and downward movement of the latch needle bars25, 26. Further, the guide bars separately make the longitudinalshogging movements required for the over and under laying of the yarnsto the latch needles, which as is controlled by well-known pattern linkchains, not shown, running over a pattern chain drum at one end of themachine. The threads in the form of groups or sets of Warp threads 45,46, 47, 48 (FIG. 4)

are fed from the four respective warp beams K K K K and over respectivethread tension rods 49, '50, 51, 52 and then through the guide fingerslocated on the eight guide bars I through VIII. The tension rods extendover the total machine length and are supported on the ends ofrespective levers 53, 54, 55, 56 which are maintained under respectivetension springs 57, 58, 59 and 60 so that the warp thread groups runningabove the rods are kept under flexible tension. The construction of theabove-described parts does not differ from that of conventional Raschelknitting machines with two needle rows for knitting fiat ribbed fabrics.Moreover, tubular hosiery blanks are now being knit in a continuousmanner on machines with two latch needle rows. However, in all suchknitted hose, the halves which form the front circumferential part ofthe stocking are continuously knit on one latch needle row and allknitted hose halves which form the back circumferential part of the hoseare continuously knit on the other latch needle row, the two knittedhose halves being interlaced at the longitudinal edges by alternatelyplacing yarn around neighboring latch needles of the two needle rows.

FIG. 5 schematically represents the covering of the latch needle rowsand the locations of the feed fingers on the corresponding guide bars.In each latch needle row Z Z for example, twelve groups of to adjacentneedles form longitudinal sections of a length indicated at B whichserve for making one tubular knitted hosiery blank. Between these groupsof active latch needles, which are shown in full black in FIG. 5, thereare some blind or dummy needles, indicated by circles. If desired, thelatch needles between the sections B may be left out completely. Incorresponding manner, the guide bars I, III, VI and VIII are alsoprovided with yarn guides, as shown by circles on the guide bars, shownas dotted lines. Compared to this, the guide bars II and VII have onlyone yarn guide 61, 62 and 63, 64 respectively, at the end of eachsection B. Guide bars IV and V each have only one yarn guide 65, 66respectively, staggered diametrically to each other and at each end ofsection B.

FIGS. 6 and 7 show the type of thread lapping, which the eight guidebars carry out during the knitting of the area of the leg length 16 ofthe stocking 10 and alternately at the front and back latch needle rowsat V and H respectively. Supposing that the pattern chain drum on theright side of the machine, with reference to FIG. 5, is located at alink of the pattern chain having a height 0, the guide bars are at theextreme right positions (FIGS. 6 and 7), that is, with reference to FIG.5 they are at their highest position, and move to the left and downwardrespectively by one latch needle distance as pattern links with heights2, 4 and 6 are moved into operative position, as indicated by thecorresponding figures 0, 2, 4 and 6 in the FIGS. 5 to 10, which will bepresently described. As illustrated in FIG. 6, a closed stitch fabricpattern is formed by the guide fingers of the guide bar I on the frontlatch needle row Z while the guide fingers of the guide bar III form atricot stitch pattern integral with this closed stitch fabric and on thesame latch needle row Z Thus, integral tricot patterns are knit on thefront latch needle row Z In the same way, the guide fingers of the guidebars VIII and VI on the back latch needle row Z lay the correspondingthreads to knit integral tricot patterns. This pattern produces a knitfabric which has double yarn stitch loops and has the advantage of beingrun-proof, even if a warp thread is torn or if there is a hole in thestocking.

The same stitch patterns are also knit along the longitudinal edges b, bat the juncture of the two circumferential sections v and h of theknitted hose by means of guide bars II, IV, V and VII. FIG. 7illustrates the movement of the guide bars in the same way as the guidebars III and VI form closed stitches alternately around two neighboringneedles of the same latch needle row Z and Z respectively. The guidebars IV and V are only equipped with the guide fingers 65 and 66respectively at the end of each section B and alternately form stitchesaround the last latch needles 67, 68, 69 and 70 respectively of the twoneedle rows at the end of each section B and thus also produce a tricotpattern. The guide fingers 61, 62 and 63, 64 respectively of the guidebars II and VII also alternately form endmost stitches around the lastactive latch needles 67, 68 and 69', 70 respectively and at oppositeends of the needle section and also around the next to last latchneedles 71, 72 and 73, 74 respectively. It is obvious that the tubularknit fabric thus produced has the same stitch pattern over the wholecircumference as is necessary for the whole leg length 16 of thestocking 10. There are only two other conditions to be met, that is,that the distance between the two latch needle rows must be the same asthe needle gauge of each row, and the thread tensions of the warp threadgroups fed to the guide bars I, II, VII and VIII and the thread tensionsof the individual warp threads fed to the guide bars III, IV, V and VImust be the same.

From the last condition it is seen that the warp beam K does not onlysupply the warp thread group for the guide bar I, but also the warpthreads for the individual guide fingers of the feed rail II. In thesame way, not only the threads for the guide fingers of the guide barVIII are taken off from the warp beam K but also those of the guide barVII. Further, the warp beam K furnishes not only the guide bar III withthe warp thread group but also supplies one warp thread each for eachsection B to the only guide finger of the guide bar IV. The warp beam Kfeeds not only the warp thread group to the guide bar VI but alsosupplies one warp thread each for each section B to the only guidefinger of the guide bar V. FIG. 4 shows this coordination of each warpbeam to two guide bars, by the divided path of the warp threads 45through 48 below the thread tnesion rods 49-52.

In order to make the reinforcements a a and a in the tubular knit halvesv and h, in accordance with the present invention, the closed stitchshogging patterns of the guide bars I and VIII (covered completely withguide fingers in the sections B) are changed to a twill stitch shoggingpattern. As is known, a twill stitch is formed by placing the threadover two latch needles with constant change of placing direction and asingle displacement from stitch row to stitch row by the gauge of oneneedle. While there is only a single placement over the first latchneedle, an open or closed stitch is formed on the second latch needle.As the case may be, either an open or a closed twill is formed.

The example of FIGS. 8 to 10 shows the placement of the threads for theformation of open twill. FIG. 8 shows the placement pattern for knittingthe bottom part a of the tubular knit section (FIG. 2), where only thefront circumferential half v is reinforced. Therefore, the twill is onlyplaced by the guide fingers of the guide bar I.

FIG. 9 shows the placement pattern for knitting the part a of thetubular knit section, where only the back circumferential half h isreinforced, and in which case only the guide fingers of the guide barVIII place the twill pattern. However, in FIG. 10 both the guide fingersof the guide bar I and the guide bar VIII place the twill pattern andthus simultaneously produce the reinforcements on both circumferentialhalves of the tubular fabric as they are required, both for the area a,of the welt and the longitudinally overlapped area of the sections a andCompared to this, the tricot placements of the guide bars III and VIremain unchanged in all areas and even on the longitudinal edges b, b ofthe circumferential halves v, h, the guide bars II, IV, V and VIIcontinue to form the tricot pattern. The thus conditioned deviations ofthe stitches along the longitudinal juncture of the edges of the twocircumferential halves v, h in the area 01 of the welt and in theoverlapping area of sections a and a are not objectionable since, whenwearing the stockings later, they are covered by the dress or skirt andshoes respectively.

As is quite obvious from a comparison of FIGS. 8 through 10 with FIG. 6,the thread requirements for the guide bars I and VIII to form the twillstitch pattern in the reinforced hose sections is considerably higherthan for the closed stitch tricot pattern in the unreinforced section.Therefore, the thread take-off speeds of the warp beams K and K have tobe in part individually and in part jointly higher, when knitting thereinforcements than when knitting the unreinforced hose sections.Further, it is indispensible when processing such fine yarns, as areused in the manufacture of hosiery, that the warp beams are drivenmechanically, that is, that they work with positive feed threadtake-off. This means that the thread take-off speeds of the warp beams Kand K must vary by large amounts and independently of each other. On theother hand, within the individual hose sections in which the placementsdo not change, the thread take-off speeds must be kept constant in orderto maintain a constant thread tension, which, because of the decreasingwarp beam diameter requires a continuous and gradual or steplessincrease of the warp beam speeds.

While the thread take-off speeds of the warp beams K and K remainunchanged, due to the ever constant placements of the warp thread groupssupplied by them, and therefore the effective diameter of these warpbeams decrease in conformity during the manufacture of each tubular knitsection A, the thread requirements on the warp beams K and K aredifferentially high because of the different lengths of the reinforcedareas a and a of the twill stitch pattern, and would actually require anindividual readjustment of the speeds of these two warp beams,independently of each other. However, in accordance with this invention,this requirement can be avoided by the fact that the coordination of thetubular knit halves of the front and back sides of the stocking with thefront and back needle beds changes from hose length A to hose length Aso that the different thread requirements on the warp beams K and Kbalances again when knitting each second knit section A. Since thedecrease in diameters of the warp beams while knitting two of suchsections A is extremely low, the diameters of the warp beams K and Kpractically decrease in conformity and allow a common stepless resettingof their speed.

FIG. 11 shows the driving parts which are required for the positivethread take-off. A sprocket is fixed on the main shaft 35 which drives,through chain 76, a sprocket 77 on an intermediate shaft 78. A gear 79,also located on the intermediate shaft 78, meshes with a gear 80 on theinput shaft of an infinitely variable transmission 81, such as a PIVtransmission. The output shaft of the infinitely variable transmission81 drives, through a bevel gear transmission 82, 83, a worm geartransmission 84, 85, and a chain drive 86, 87, 88, the warp beam K Thewarp beam K is driven through a pair of gears 89, which serves only toreverse the rotary direction, and another chain drive 91, 92, 93. Sincethe pairs of gears 89, 90 and sprockets 91, 93 have the same measurements, it is understood that the two intermediate warp beams K and Kare synchronously driven in opposite directions.

The speed of the infinitely variable transmission 81 is adjusted by areversible motor 95 acting through a reducing gear 94. The operation ofthe motor can be delayed for selected periods by a time relay 96, whichis adjustable by a setting button 97. The direction of rotation of themotor 95 depends on which of two limit switches 98, 99 receives animpulse from fingers 100, 101, located on the tension lever shaft 55,when the corresponding thread tension rod (FIG. 4) swings beyond one orthe other side of the normal swing range for the desired thread tension.The motor 95 is thereby switched on temporarily and changes the gearratio of the infinitely variable transmission 81 so that the threadtension lever 7 51 returns to its normal swing size. By the correctregulation of the set button 97, the switch on time of the relay 96 isvaried to avoid both an overswinging to the other side of the swingrange and a too-frequent switching on of the motor from the sameoverswing side. Due to the identical diameters of the warp beams K and Kand their synchronous drive in connection with the same threadrequirements for both warp beams, the thread tension rod 50 (pertinentto the warp beam K in the position of its swing range) always harmonizeswith the thread tension rod 51 of the-warp beam K so that all warpthreads supplied from these two beams have always the same tension andproduce a uniform tricot weave all over the tubular knit circumference.

In accordance with the invention, only one infinitely variabletransmission 102 is provided for driving the warp beams K and K withpartly different speed. The infinitely variable transmission is drivenby the second main shaft 36 of the machine through a chain drive 103,104, 105 and a pair of gears 106, 107. However, on the output side ofthe infinitely variable transmission 102, this drive line is on the onehand branched off through bevel gears 108, 109 to a two-step change geardevice 110 and on the other hand through a chain drive 111, 112, 113 anda pair of bevel gears 114, 115 to another or second two-step change geardevice 116. An output shaft 117 of the change gearing 116 drives,through a worm gear transmission 118, 119 and a chain drive 120, '121,122, the warp beam K An output shaft 123 of the change gearing 110drives, through a worm gear transmission 124, 125 and a chain drive 126,127, 128, the warp beam K The two change gearings 110, 116 are identicaland are changed by adjusting devices 129, respectively, which act onrespective keys 131, 132. The keys 131, 132 can be shifted between thepositions shown to change the rotational speeds of the respective outputto the degree required. It is not necessary to comment any further onthe design and function of such two-step or two-speed change gearings,since the expert in this technical field is very familiar with them. Asuitable speed adjusting device is represented and described for examplein French Pat. No. 1,488,796. As a matter of fact, other shift or changegear transmissions with any adjusting devices may be used instead ofthis gearing, as long as they have the gear ratios required for theindividual shift phases and their change can be controlled by theprogrammer of the machine with the necessary speed.

In order to adjust the infinitely variable transmission 102, as in thecase of the infinitely variable gear 81, a reversible motor 133 isprovided with reducing gear 134 and, this time, a time relay 139 withcontrol set button 140. The motor 133 is controlled by the lever shaft56 through fingers 135, 136 and corresponding limit switches 137, 138.The interior control of the timed relay is, for example, described inthe U.S.A. patent specification 3,364,403. Other control devices canalso be used for the infinitely variable transmissions 81, 102 insteadof the respective limit switches 98, 99 and 137, 138 and the respectivetime relays 96 and 139, if they are suitable to readjust the gear ratiosof the infinitely variable transmissions 81, 102 so that thread tensionrods 49, 50, 51, 52 are returned to their normal operating area.

The change of gearings 110, 116 is controlled by the programmer of themachine, which in most cases will be formed by a paper tape or cards,and simultaneously with the change of the pattern chains to knit othertype of stitch patterns of the warp threads fed from the warp beams Kand K In accordance with the invention, the programmer is so programmedthat the tubular knit half v of one hose length A (FIGS. 2 and 3) isknit on the front needles Z and the corresponding threads are fed fromthe first two warp beams K and K Then, the tubular knit half 1 of thenext successive hose length A is knit on the rear needles Z and thecorresponding threads are fed from the last two warp beams K and K Thisprocedure reverses with the knitting of each successive hose length A sothat the different thread take-01f and consumption for each hose lengthA from the warp beams K and K constantly balances and their effectivediameters also decrease uniformly and the tensions of the Warp threadsfed from these beams are exactly identical at the same switchingposition of the change gearings 110, 116, particularly at the switchingpositions between the knitting of the reinforced sections and theunreinforced leg area 16 of the hose 10.

In the drawings and specification there has been set forth a preferredembodiment of the invention and although specific terms are employedthey are used in a generic and descriptive sense only and not forpurposes of limitation.

I claim:

1. In a flat warp knitting machine for knitting successivelyinterconnected seamless hosiery blanks having reinforced stitch patternsin selected areas and including front and rear needle rows, a pluralityof positively driven warp beams feeding sets of warp threads to saidneedle rows, and warp thread guide means for feeding the warp threads tosaid needle rows to form one circumferential half of each hosiery blankon each needle row and to interknit the halves at opposed edges, andwherein one circumferential half of each hosiery blank includes agreater length of the reinforced stitch pattern than the other half sothat the knitting of said one half consumes a greater length of the warpthreads than the knitting of the other half; the combination therewithof means for uniformly controlling the positive take-off of thread fromsaid warp beams, said control means comprising (a) means for knittingsaid one half of alternate hosiery blanks of threads fed from certainwarp beams while knitting said other half of alternate hosiery blanks ofthreads fed from other warp beams, and

(b) means for knitting said one half of intervening hosiery blanks ofthreads fed from said other warp beams while knitting said other half ofintervening hosiery blanks of threads fed from said certain warp beamsso that the length of threads fed from said certain and said other warpbeams is equalized over the period of the knitting of a number ofhosiery blanks.

2. A knitting machine according to claim 1 wherein said positive threadtake-off means includes change gear transmission means for switching therotative speed of selected warp beams to increase the speed thereofduring the knitting of the reinforced areas of the hosiery blank and toreduce the speed thereof during the knitting of the remaining areas ofthe hosiery blank.

3. A knitting machine according to claim 2 including infinitely variabletransmission gear means drivingly connected to said change geartransmission means, and control means for said infinitely variabletransmission gear means for gradually increasing the rotative speed ofsaid selected warp beams as the warp threads are fed therefrom and asthe diameters decrease.

4. A knitting machine according to claim 3 wherein said control meansincludes means operable in response to variations in the tension on thewarp threads to adjust said infinitely variable transmission gear means,and time delay relay means preventing the operation of said controlmeans with momentary variations in tension on the Warp threads.

5. A knitting machine according to claim 1 wherein said plurality ofwarp beams includes first and second warp beams feeding threads to saidfront needle row and third and fourth warp beams feeding threads to saidrear needle row during the knitting of a given hosiery blank, andwherein said positive thread take-01f means includes separate changegear transmission means drivingly connected to said first and fourthwarp beams for switching the rotative speeds of said Warp beams toincrease the speed thereof durin the knitting of the reinforced areas ofthe hosiery blank, common infinitely variable transmission gear meansdrivingly connected to each of said separate change gear transmissionmeans for gradually increasing the rotative speed of said first andfourth Warp beams as the Warp threads are fed therefrom and as thediameters decrease, and second infinitely variable transmission gearmeans drivingly connected to said second and third warp beams forgradually increasing the rotative speed of the same as the warp threadsare fed therefrom and as the diameters decrease.

References Cited UNITED STATES PATENTS Bassist 6686 Lambach et a1. 66-86Bassist 6686 Bassist 6686 Liebchen 6686UX Perrier 66195 10 RONALDFELDBAUM, Primary Examiner

